"These all give us great pause and concern as well as that Ohio falls below the national average when it comes to children who have the complete line of vaccinations," Antonio said in a news conference Wednesday.

An estimated 66.8 percent of Ohio children age 19 to 35 months received the combined vaccine series including MMR, according to the 2012 National Immunization Survey. The national average was 68.4 percent.

Under existing state law, parents submit a medical form to the child care provider. Under House Bill 536, Antonio said, the form would include space to note immunizations and require a physician's signature to be complete.

"At the end of the day, we believe immunizations are very important, preventative health care is extreme important," said joint sponsor Rep. Ryan Smith, a Bidwell Republican. "As the father of four, it's important to me."

Dr. Jonathan Thackeray, chief of center for family safety and healing at Nationwide Children's Hospital, said vaccine education, not access, has kept many children from being immunized.

"Parents are scared to vaccinate their children and their fears are based on old science that has been shown to be poor and inaccurate," Thackeray said.